It is the French equivalent of soured cream and is thicker and richer than the British sour cream. Prepared by adding lactic bacteria culture to cow’s milk, which thickens and gives it a sharp flavour, it is used to lace soups, sauces and stews. A close version can be prepared at home by gently heating plain yoghurt. This is a good replacement for the otherwise expensive crème fraiche readily available in the market.

The best crème fraîche comes from a

strictly controlled area of Normandy called Isigny-sur-Mer and it's sold in tubs and has a longer shelf-life than double cream so you can store it in the fridge for a couple of weeks and use it as and when you need it.